2-甲酯基噻吩-3-重氮四氟硼酸盐的钯催化的松田-的Heck和Suzuki-Miyaura交叉偶联1进行到合成一系列在β位官能噻吩衍生物。使用乙酸钯[Pd(OAc)2 ],一种无配体的钯催化剂,无碱,在室温下,好氧条件下,反应时间短的情况下,可获得良好或优异的交叉偶联产物收率。重氮化和交叉偶联的序列也可以在一锅法中进行,从而避免了噻吩并重氮盐衍生物的分离。此外,2-甲氧基羰基苯并[ b ]噻吩-3-重氮四氟硼酸盐8 通过应用相同的Suzuki-Miyaura优化反应条件也可以有效地芳基化。
Ru-Catalyzed (<i>E</i>)-Specific <i>ortho</i>-C–H Alkenylation of Arenecarboxylic Acids by Coupling with Alkenyl Bromides
作者:Zhiyong Hu、Florian Belitz、Guodong Zhang、Florian Papp、Lukas J. Gooßen
DOI:10.1021/acs.orglett.1c00956
日期:2021.5.7
alkenyl bromides, (E)-configured vinyl arenes or dienes are formed exclusively. Mechanistic studies show that this selectivity is achieved because the (E)-configured alkenyl bromides undergo a smooth coupling, whereas the (Z)-isomers are rapidly eliminated with the formation of alkynes.
Gold catalyzed Heck-coupling of arenediazonium <i>o</i>-benzenedisulfonimides
作者:Margherita Barbero、Stefano Dughera
DOI:10.1039/c7ob02624b
日期:——
Diazonium salts, and precisely arenediazonium o-benzenedisulfonimides, have been used for the first time as efficient electrophilic partners in gold catalyzed Heck-coupling reactions. The synthetic protocol was general, easy and gave the target products in satisfactory yields. Mechanistic insights revealed the fundamental roles of the o-benzenedisulfonimide anion as an electron transfer agent thath promotes
styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the αposition has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 αselectivity. The key to our success is a new ferrocene 1,1′‐bisphosphane (dnpf) that carries 1‐naphthyl groups. Our mechanistic studies revealed that the high α selectivity
thiophene-2-carboxylic acids can be achieved effectively via rhodium/silver-catalyzed oxidative coupling with alkenes, unaccompanied by decarboxylation. A wide range of substrates including brominated thiophenecarboxylic acids and furan-2-carboxylic acids can be employed together with styrenes as well as acrylates. The present catalyst system is also applicable to ortho-alkenylation of benzoic acids.